UNIX 6th Ed. - /usr/source/s1/cp.c

   1: /*
   2:  * cp oldfile newfile
   3:  */
   4: 
   5: main(argc,argv)
   6: char **argv;
   7: {
   8:     static int buf[256];
   9:     int fold, fnew, n;
  10:     register char *p1, *p2, *bp;
  11:     int mode;
  12: 
  13:     if(argc != 3) {
  14:         write(1, "Usage: cp oldfile newfile\n", 26);
  15:         exit(1);
  16:     }
  17:     if((fold = open(argv[1], 0)) < 0) {
  18:         write(1, "Cannot open old file.\n", 22);
  19:         exit(1);
  20:     }
  21:     fstat(fold, buf);
  22:     mode = buf[2];
  23:     /* is target a directory? */
  24:     if (stat(argv[2], buf+50)>=0 && (buf[52]&060000)==040000) {
  25:         p1 = argv[1];
  26:         p2 = argv[2];
  27:         bp = buf+100;
  28:         while(*bp++ = *p2++);
  29:         bp[-1] = '/';
  30:         p2 = bp;
  31:         while(*bp = *p1++)
  32:             if(*bp++ == '/')
  33:                 bp = p2;
  34:         argv[2] = buf+100;
  35:     }
  36:     if (stat(argv[2], buf+50) >= 0) {
  37:         if (buf[0]==buf[50] && buf[1]==buf[51]) {
  38:             write(1, "Copying file to itself.\n", 24);
  39:             exit(1);
  40:         }
  41:     }
  42:     if ((fnew = creat(argv[2], mode)) < 0) {
  43:         write(1, "Can't create new file.\n", 23);
  44:         exit(1);
  45:     }
  46:     while(n = read(fold,  buf,  512)) {
  47:     if(n < 0) {
  48:         write(1, "Read error\n", 11);
  49:         exit(1);
  50:     } else
  51:         if(write(fnew, buf, n) != n){
  52:             write(1, "Write error.\n", 13);
  53:             exit(1);
  54:         }
  55:     }
  56:     exit(0);
  57: }

Defined functions